In standardization of 3GPP Long Term Evolution (LTE), PARC (Per Antenna Rate Control) scheme, which is one of MIMO (Multi Input Multi Output) transmission schemes, is discussed. In PARC, modulation and coding schemes are selected according to channel quality (CQI) report values on a per transmission antenna (stream) basis. Patent Document 1 discloses a conventional MIMO PARC scheme.
FIG. 1 shows a configuration of the MIMO transmitting apparatus in the MIMO communication system adopting the conventional MIMO PARC scheme. As shown in the figure, the MIMO transmitting apparatus transmits pilot signals on a per antenna basis by using several subcarriers. On the other hand, the receiving apparatus (not shown) measures the received intensity of each pilot signal transmitted from the antennas in the MIMO transmitting apparatus, generates a CQI (channel quality indicator) per antenna based on the channel quality condition for each antenna, and feeds back the CQIs to the MIMO transmitting apparatus. The MIMO transmitting apparatus determines the optimal modulation scheme (QPSK, 16QAM, 64QAM and so on) and coding rate on a per antenna basis based on the CQI information per antenna and transmits substreams from the antennas. In this way, by selecting optimal modulation and coding scheme based on the channel quality condition of each antenna, the maximum peak rate and communication capacity are achieved.
Non-patent Document 1: Lucent 3GPP R1-010879